How does aspirin affect platelet function?

Aspirin affects platelet function primarily by irreversibly inhibiting cyclooxygenase (COX), which is a crucial enzyme in the pathway that produces thromboxane A2 (TXA2). Thromboxane A2 is a potent promoter of platelet aggregation and vasoconstriction. By inhibiting COX, aspirin effectively reduces the formation of thromboxane A2. This leads to a decrease in platelet aggregation, making aspirin an important medication in preventing thrombotic events like heart attacks and strokes.

The mechanism of action is significant because the effect of aspirin on platelets lasts for the lifespan of the platelet itself, which is about 7-10 days, as new platelets must be produced to restore normal function. This is why aspirin is often used in low doses for cardiovascular protection. Understanding this action helps in grasping how aspirin contributes to its role in preventing clot formation and reducing the risk of cardiovascular events.